Assessment of the antimutagenic effect of Doash tea extract fractions

Hyperforin Exhibits Antigenotoxic Activity on Human and Bacterial Cells

Hyperforin (HF), a substance that accumulates in the leaves and flowers of Hypericum perforatum L. (St. John’s wort), consists of a phloroglucinol skeleton with lipophilic isoprene chains. HF exhibits several medicinal properties and is mainly used as an antidepressant. So far, the antigenotoxicity of HF has not been investigated at the level of primary genetic damage, gene mutations, and chromosome aberrations, simultaneously. The present work is designed to investigate the potential antigenotoxic effects of HF using three different experimental test systems. The antigenotoxic effect of HF leading to the decrease of primary/transient promutagenic genetic changes was detected by the alkaline comet assay on human lymphocytes. The HF antimutagenic effect leading to the reduction of gene mutations was assessed using the Ames test on the standard Salmonella typhimurium (TA97, TA98, and TA100) bacterial strains, and the anticlastogenic effect of HF leading to the reduction of chromosome aberrations was evaluated by the in vitro mammalian chromosome aberration test on the human tumor cell line HepG2 and the non-carcinogenic cell line VH10. Our findings provided evidence that HF showed antigenotoxic effects towards oxidative mutagen zeocin in the comet assay and diagnostic mutagen (4-nitroquinoline-1-oxide) in the Ames test. Moreover, HF exhibited an anticlastogenic effect towards benzo(a)pyrene and cisplatin in the chromosome aberration test.

Antimutagenic and anticancer activity of Darjeeling tea in multiple test systems

Background

Darjeeling tea, a most popular variety of black tea, though consumed by the people in different parts of world but its beneficial health effects have not been investigated in details. In this study, the antimutagenic and anticancer effect of Darjeeling tea extract (DTE) has been evaluated.

Methods

Antimutagenic activity of the DTE was carried out in two different strains of Salmonella typhimurium by AMES test against a known mutagen benzo[a]pyrene (B[a]P) with S9 activation. Moreover, anticlastogenic property of DTE was also measured by micronuclei formation (MN) against B[a]P with S9 activation in human lymphocytes. The anticancer activity of the same was studied on U937 cell line. Here, Human PBMCs were used as the normal cell control to identify selective anticancer activity of the extract against U937 cells.

Results

The results showed significant antimutagenic activity on bacterial strains. A significant decrease in MN was also observed in the DTE treated human lymphocyte cultures pretreated with B[a]P when compared with B[a]P treated cultures alone. The study clearly exhibited anticancer activity of the extract on U937 cell line. Further studies also revealed that apoptosis induction is an important mechanism behind the anticancer effect of DTE.

Conclusion

Overall, this study indicates that DTE has significant antimutagenic and anticancer activities on bacterial and mammalian cells respectively.